Felting apparatus



y 2, 1956 L. cs. BAXTER ETAL 2,746,096

FELTING APPARATUS Filed March 15, 1951 2 Sheets-Sheet l A 77'0ENEY y 22,1956 1.. G. BAXTER ErAL FELTING APPARATUS 2 Sheets-Sheet 2 Filed March13 1951 VENTOR United States Patent F FELTING APPARATUS ApplicationMarch 13, 1951, Serial No. 215,312

Claims. (Cl. 19-155) The present invention pertains to felting apparatusand particularly relates to apparatus useful in the formation of mats orfelts adapted to be compressed for the manufacture of consolidatedproducts such as composition boards, particularly hardboard.

Both wet and dry methods are used conventionally in fabricatingconsolidated composition products such as hardboard. In the wet method,wood fiber or other suitable material is suspended in a thin waterslurry. The latter is drained through a screen on an elaborate andexpensive forming apparatus to form a wet lap or felt which then may bedried and pressed to form the consolidated product. This method resultsin the production of a felt which is uniform in thickness and which maybe consolidated into a board having uniform density and strength acrossits width. However, the necessity of employing elaborate feltingapparatus, of incorporating the fibers in an aqueous suspending medium,and of handling large volumes of water impose serious limitations on theeconomy of the method.

In the dry felting method, on the other hand, Wood fiber or similarmaterial is used directly without benefit of an aqueous suspendingmedium,:although the fiber itself may have a substantial water content.The dry or moist fibers are formed directly into a felt of the desiredthickness which then is pressed to form the consolidated product. Thisobviously is a much more direct felting method than is the wet method,but it is one in which many problems are inherent.

In the first place, it is difiicult to form a dry felt of uniformthickness, and elaborate leveling and smooth ing means have beenprovided in prior art apparatus for securing a felt satisfactory in thisrespect. It is apparent that if the felt is not uniform, theconsolidated product prepared therefrom will be defective in that itwill be of nonuniform density and strength.

Secondly, it is difiicult to provide dry felting apparatus which informing into felt fibers of varying dimensions, will not separate thefibers according to their particle size, i. e. separate the fine fromthe coarse, with the result that a laminated felt will be formed. Thisin turn will produce a board which is relatively weak at the point oflamination and which is prone to warp.

Still further, it is difiicult in dry felting to provide apparatus whichwill deposit the fibers individually, since they tend to cling togetherand to be deposited in the form of fiber clumps or flocs. Also, if thefibers are elongated, they tend to lie in the same general direction inthe felt and produce an oriented felt. Both of these factors alsoproduce a structurally weak consolidated product.

Another point of difliculty in dry felting operations is that ofproviding apparatus which is flexible and will deposit the fiber at anyone of a number of predetermined rates, and which may be applied to thebuilding of a felt of any desired thickness. It is difiicult,furthermore, to control the thickness of the felt at the side edges toavoid the formation, through fiber squeeze out during 2,746,096 PatentedMay 22,

2. pressing, of marginal board areas of reduced density which must betrimmed ofi. Hence, all of the above factors must be controlled if thefelting apparatus is to be suitable for commercial operation,particularly if it is to make a product comparable in properties to thatproduced by the conventional Wet felting apparatus.

It therefore is a primary object of the present invention to provide apractical and commercially operable apparatus for use in the productionof a consolidated fibrous product by the dry felting method.

Still another object of the present invention is the provision of dryfelting apparatus which will produce consolidated products of uniformdensity and strength.

Still another object of the present invention is the provision ofapparatus for dry felting fibrous material of non-uniform dimensionswithout separation of the fine and coarse particles into laminae, which,if present, would impart to the final consolidated product anundesirable laminated structure.

Another object of this invention is the provision of dry feltingapparatus in which the felted particles are completely randomized as tofiber direction.

Another object of the present invention is the provision of dry feltingapparatus which will form a felt free from fiber clots and fiocs.

Still a further object of the present invention is the provision of dryfelting apparatus which will deposit a felt having relatively thick sidemargins with the result that the consolidated product made from the feltwill have the required thickness and density across substantially itsentire width.

Still a further objectof the present invention is the provision of dryfelting. apparatus adapted to the continuous formation of a felt, buteliminating the necessity of providing means for sawing or cutting acontinuous felt into blanks of the required length for insertion in thepress.

Another object of the present invention is the provision of dry feltingapparatus which is completely flexible and may be controlled preciselyas to the rate of fiber deposit and thickness of felt produced.

Another object of the present invention is the provision of dry feltingapparatus in which the felt may be deposited directly on the press caulplates, thereby eliminating the necessity of providing transferapparatus for transferring the felt from the felting apparatus to thecaul plates.

Still another object of the present invention is the provision of dryfelting apparatus which will produce a felt of uniform thickness withoutthe necessity of providing separate smoothing and leveling means.

Still a further object of the present invention is the provision of dryfelting apparatus which is simple in construction and economical tooperate.

The manner in which the foregoing and other objects of the presentinvention are accomplished will be apparent from the accompanyingspecification and claims considered together with the drawings wherein:

Figure l is a view in perspective of the dry felting apparatus of thepresent invention, the structure being partly broken away better toreveal its construction;

Figure 2 is a detail sectional view in elevation taken along the line 22of Figure 1 Figure 3 is a detail sectional view taken along the line 3-3of Figure 2;

Figure 4 is a sectional view in elevation taken along the line 44 ofFigure 1;

Figure 5 is a fragmentary view in elevation illustrating an alternateform of the presently described apparatus; and

Figures 6 to 9 inclusively are perspective fragmentary 3 s u t i va i tyes. tt r-divi means applicable in the felting apparatus of Figure 1.

Generally stated the felting apparatus of this invention comprises afelt support or conveyor means having a foraminous cylinder or drumrotatably mounted above it. The cylinder is positioned transversely ofthe conveyor and preferably contains a plurality of tumbling blocks.Brushing means such as a brushing roll is rotatably mounted above thedrum parallel thereto and in peripheral contact therewith. Also, abaffle plate is stationed above the cylinder parallel thereto and infrictional engagement therewith a spaced distance ahead of the brushingroll'. This forms a chamber defined on three sides by the brushing roll,the bafile plate, and the upper surface of the foraminous cylinder.

Means also are provided for feeding wood fiber or similar comminutedmaterial into the chamber formed by the above members. Upon rotation ofthe drum, this material sifts through the upper surface of the same,being restrained from following the outer surface of the drum by thebrushing roll and being directed toward the tumbling blocks by thebaffle plate. The fiber feeding means preferably is reciprocable so thatthe fiber is distributed substantially uniformly along the length of thecylinder.

Within the cylinder the fibrous material is completely separated intoits component fibers by the action of the tumbling blocks, and thefibers are completely randomized, i. e. unoriented as to fiberdirection. After they filter down through the tumbling blocks they passthrough the lower surface of the foraminous cylinder and rain down uponthe conveyor. There they build up a felt having a thickness determinedby the rate of fiber fiow and the speed of the conveyor. The latterpreferably carries caul plates in edge to edge relationship anddimensioned to fit the press to be used in consolidating the felt.Preferably also, the conveyor is provided with transverse dividing meansto facilitate the division of the felt into blanks codirnensional withthe caul plates in a manner to be explained in detail hereinbelow.

Referring now more particularly to the drawings:

The presently described dry felting apparatus is operated in conjunctionwith felt support means such as the endless conveyor belt 10. This ismounted on rolls 12, 14 at least one of which may be driven throughcontrol means making possible driving of the belt at any suitable speed.Directly attached to the conveyor belt are a plurality of dividers 16extending transversely of the belt and positioned a spaced distance fromeach other, the spacing being determined by the length of the fibrousblanks it is desired to prepare.

Caul plates 18 dimensioned to fit between the dividers 16 rest upon theconveyor belt. These are made of steel, aluminum or other suitable metaland are adapted to support the felt 20 and to be used in conveying thesame to a suitable press where it may be consolidated by the applicationof pressure and heat. In this way it is possible to felt directly uponthe caul plates and to eliminate the expense and complications attendantupon transferring a bulky felt, which is not self sustaining, from theconveyor belt to the caul plates of the press.

Rotatably mounted in a housing 22 of suitable construction andpositioned above the conveyor belt 10 is a foraminous cylinder or drum25. This extends transversely of the conveyor a spaced distancethereabove. It may comprise a metal cylinder having perforationsQfsuitable diameter, or preferably a screen cylinder having a mesh sizesuitable for passing or transmitting the fibrous material to be felted.Cylinder 25 may be rotatably mounted within the housing in any suitablemanner, as by being-journaled thereto or preferably by being providedwith a ring gear 28 externally of the housing. Gear 28 engages a pair ofpinion gears 30, 32. One of the latter, e.. g. gear 32, is mounted onthe same shaft with a pulley wheel 34 interconnected by belt 36 topulley wheel 38 on a variable speed motor 40.

In this manner means are provided for driving the cylinder at anydesired speed.

Although fibers introduced into cylinder 25 may be randomized anddistributed to a certain degree solely by the action of the rotatingscreen, these desirable results may be attained to a much higher degreeby placing within the cylinder a quantity of tumbling blocks 42 whichserve as tumbling battles to divert the fiber flow. The tumbling blocksor batfles may comprise solid pieces of material such as wood blocks,metal or plastic spheres or inert solid objects which are 'sufiicientlylarge to be retained in the foraminous cylinder. In practice, plywoodblocks inch thick and about 1 inch square have been found well suitedfor this purpose, where the mesh size of the cylinder screen is aboutinch.

Means also are provided for supplying fibrous material to the uppersurface of the cylinder where it sifts through the same down into thetumbling blocks, thus securing maximum separation and randomizing of thefibers. To this end there is provided above the cylinder and parallelthereto brushing means which preferably comprise a rotary cylinder 44having blades 46 which are in peripheral engagement with the cylinder.The brushing roll 44 is rotatably mounted on the housing 22 as by beingjournaled thereto and preferably is driven directly from cylinder 25.Thus the latter cylinder may have attached thereto pulley wheel 48 whichis connected through belt 50 to pulley wheel 52 on the shaft of brushingroll 44. Then as cylinder 25 rotates, it will drive brushing roll 44 ata rate determined in part by the differential in diameter of pulleys 48and 52.

Further to promote the passage of fibrous material into cylinder 25,there is provided a bafiie plate 54 which like brushing roll 44 liesparallel to cylinder 25. Plate 54 preferably has a blade of resilientmaterial which is in peripheral contact with the outer surface of thecylinder.

In this manner there is formed a chamber or compartment defined on threesides by the brushing roll, the baflle plate and the upper peripheralSurface of the cylinder. When fibrous material is introduced in thischamber, it passes through the foraminous cylinder onto the tumblingblocks, being guided by bafile plate 54. During this operation brushingroll 44 rotating counterclockwise in the same direction as theforaminous cylinder (Fig. 4) prevents passage of fiber over the top ofthe cylinder and also assists in driving the fibrous particles throughthe foramens of the cylinder.

The amount of fibrous material passing through the cylinder in a giventime will be determined by several factors such as the character of thefiber, the relative sizes of the foramens and the fiber particles, theeffect of the brushing roll, the rate of feed of fibrous material to theupper surface of the cylinder, and the cylinder surface area in contactwith the fibers between the brushing roll 44 and the b'afiie plate '54.Since it may be desirable to adjust the rate of fiber flow through thecylinder from time to time, means are provided for varying the surfacearea of the cylinder which is in contact with the fibers. To this endthe distance between brushing roll 44 and the baffle plate 54 may bemade variable as by making one or more of these members adjustable. Inthe illustrated embodiment the brushing roll is made adjustable, as forexample, by extending the shaft thereof through an arcuate slot 56 inhousing 22 and fastening the bearings 58 mounting the shaft at stationscorresponding to the desired spacing between the brushing roll and thebafiie plate.

The action of the means employed for supplying fibrous material to thespace between brushing roll 44 and baffle plate 54 preferably -'is suchas to distribute'the fiber along the length of the cylinder, rather thandepositing it all in one place. As is illustrated in Figure 5 there maybe supplied conduit means such as a spout 60 connected through a balland socket joint 62 or other flexible-union to a conduit 64communicating with'a source of fibrous material. Means then are providedfor oscillating spout- 60 so that it moves along the length of thecylinder, distributing fiber thereon as it goes. Such a means maycomprise, for example, a fluid operated cylinder such as the air orhydraulic cylinder 66, the piston rod 68 of which may be pivotallyconnected through link 70 to spout 60.

When the oscillating conduit employed is of substantial length, asfifteen feet or more, the rate of gravitational fiber fiow therethroughwill be substantially uniform since the conduit will be almost verticalalong its entire arc. However, when a relatively short conduit is used,a problem in fiber flow is presented by reason of the fact that thefiber fiows more rapidly through the conduit when the latter is in avertical position than when it is extended angularly to either side. Asa result, the distribution of fiber on the surface of the cylinder willnot be uniform, a greater quantity being deposited in the middle portionof the arc than in the terminal portions.

For this reason an oscillating conduit preferably is provided whichmoves faster through the central portion of its arc than at the terminalportions thereof. Such a conduit is illustrated in Figures 1 and 2. Inthe embodiment of these figures, the spout 72 is connected through aflexible union such as the ball and socket joint 74 to a conduit 76communicating with a fiber source. The outlet of the spout is disposedwithin the housing 22 above the cylinder and directed toward bafiieplate 54 (Figure 4).

The driving means employed to oscillate the spout comprises a continuousflexible member such as the chain 78 arranged in a vertical arc in adirection parallel to the longitutional axis of the cylinder. Chain 78is maintained in the desired arcuate form by means of an upper chainguide 86, and a lower chain guide 82, these being supported by means ofbrackets 84, 86. The chain assembly includes the idler sprocket 88rotatably mounted on the housing of the apparatus and the drivensprocket 90. The latter is connected to the variable speed motor 92through pulleys 94 and 96 and the interconnecting belt 97.

S out 72 is attached to chain 78 by suitable means, such as the plate 98fastened through pivot pin 99 to flanged roller 100, which moves inguideway 102 extending longitudinally along the lower portion of spout72. It thus will be apparent that as the spout is driven by the chain,the rate of travel will be relatively great along the center portion ofits path and relatively slow along the terminal portions because thehorizontal travel component of the arcuate chain is greater at itsmiddle portion than at its ends. Also, the spout will pause momentarilywhen it reverses the direction of its travel at the end of each passbecause at these two points the direction of travel of the chain issubstantially vertical. This results in a slightly increased deposit offibrous material along the extreme side edges of the felt.

Where the felt is deposited directly on the caul plate it will beseparated into the desired lengths as the caul plates are removed fromthe conveyor 11 However, it is preferred to provide dividing means toassist in this operation. It has been found that a continuous divider,such as divider 16, is not necessary for this purpose since the felt issufiiciently weakened for separation by the presence of even adiscontinuous divider.

Thus various forms of discontinuous dividers such as are illustrated inFigures 7 to 9 inclusive may be used, these having the advantage ofbeing light in weight and not subject to breakage. In the embodiment ofFigure 7, for example, the dividing means may comprise a transverse rowof spikes or studs 1G4 fastened to the conveyor belt 106. When thefibrous material is deposited on these, the resulting felt will have acorresponding series of weakened areas which enable its ready separationat the desired point.

- Similarly the dividing means may comprise a bar 103 6 extendingtransversely of the conveyor 112 and main tained a spaced distance aparttherefrom by means of the supporting legs (Figure. 8). In still anotherform, the dividing means may comprise simply a bar 114 maintained apartfrom the conveyor 116 by the support means 118. In the constructions ofFigures 8 and 9 the bar preferably is maintained at an elevationsubstantially on the same plane as the upper surface of the felt so thatit creases or indents the latter, forming a transverse area of fiberdeficiency which permits separation of the felt in the desired place.

In operation, fiber which preferably has been admixed with a suitableadhesive is fed at a controlled rate through conduit 76 to oscillatingspout 72. It is distributed by means of this spout along the uppersurface of cylinder 25. The distribution is uniform along the greaterpart of the spout travel, the vertically arcuate configuration of thespout driving chain 78 serving to move it most rapidly through thecentral portion of its travel at-which it is substantially vertical andfibrous flow therethrough is correspondingly great. However, during themomentary pause occurring as the chain reverses its direction at theterminal portions of its arc, a slightly increased amount of fiber ispermitted to fiow, building up a felt of increased thickness along itsside edges. This compensates for squeeze-out in the press and reducesthe amount of trim in the finished panel, as explained above.

Fiber distributed from the spout on the exterior surface of theforaminous cylinder is directed toward the tumbling blocks 42 containedtherein by means of baffle plate 54. Any excess fiber which might becarried over the top of the cylinder is prevented from so doing by meansof brushing roll 44, which serves the additional important function oflip-ending the fibers so that they pass through the openings of thecylinder more readily. The rate of flow of the fibers through thecylinder may be readily controlled by varying the rate at which it isfed from spout 72 as well as by adjustment of the space separatingbrushing roll 44 and baffle plate 54 to provide more or less surface ofthe cylinder therebetween.

As the fibers enter the drum they are engulfed by the tumbling blockswhich separate any clumps or aggregates of fiber into completelyrandomized individual fibers. These then gravitate downwardly throughthe lower surface of the cylinder and sift onto conveyor 10 orpreferably onto caul plates 18 carried thereby.

This results in the formation of a felt of uniform thickness (except forthe marginal beads of slightly increased thickness), the fiber contentof which is completely randomized and the component fibers of which areintimately mixed with each other regardless of their size. Consequentlythe fibers are completely unoriented in the felt and the fine and coarsefibers are uniformly mixed with each other. This leads to the productionof a consolidated board which will not delaminate and which is ofuniform strength and density across its entire surface.

The mode of operation of the presently described apparatus and thebenefits accruing therefrom are further illustrated in the followingexample:

A dry felt was prepared in apparatus of the type described above whereinthe cylinder had a diameter of 24 inches and a length of 52 inches, andwas covered with a three-fourths inch mesh screen. It was filled withtumbling blocks comprising plywood blocks 1 inch square andthree-eighths inch thick. The cylinder was rotated at a speed of 10 R.P. M. and the brushing roll at 50 R. P. M. Kiln dried Douglas fir fiber,having a maximum length of about 6.5 inch, which had previously beenmixed with about 3 by weight of phenol-aldehyde binder was fed to theupper surface of the cylinder by meansof reciprocating spent at a rateof 200 pounds per hour. The felt was built up on caul plates to a depthof three inches after which it was consolidated to a thickness of inchin a heated hydraulic press maintained at a temperature Board strengthand gravity variation perpendicular to machine direction SpecificGravity 1 lrxug llgllgpeulus of Distance From a i Commer- Edge (Inches)Comruerct Dry Felted cial Wet q 1- l Hal'dboard Felted Hartlboard.Hardboard p. iv 1.00 Sp. (lr.

It is to be understood that the forms of our invention herewith shownand described, are to be taken as preferred examples of the same, andthat various changes in the shape, size and arrangement of parts may beresorted to, Without departing from the spirit of our invention, or thescope of the sub-joined claims.

Haring thus described our invention, we claim:

1. Felting apparatus comprising conveyor means; a foraminous drumrotatably mounted above the conveyor means; a brushing roll rotatablymounted above the drum parallel thereto and in peripheral contacttherewith; a bafile plate stationed ahead of the brushing roll parallelto the drum and in peripheral contact therewith, thereby forming achamber three sides of which are defined by the brushing roll, thebafiie plate and the upper surface of the drum; and fiber feeding meansfor feeding fibrous material into the chamber, the rotation of thebrushing roll and the drum acting to sift the material through the drumand to deposit it in a uniform layer upon the con veyor means.

2. Felting apparatus comprising conveyor means; a foraminous drumrotatably mounted above the conveyor means; a brushing roll rotatablymounted above the drum parallel thereto and in peripheral contacttherewith; a baffle plate mounted a spaced distance ahead of thebrushing roll, the baffle plate being parallel to the drum and inperipheral contact therewith, thereby forming a chamber defined on threesides by the brushing roll,'the

bafile plate and the upper surface of the drum; feeding means forfeeding fiber into the chamber; and motor means for rotating the drumand the brushing roll, thereby-sifting the fiber through the drum at arate determined by the spacing between the brushing roll and the bafiletit) 8 plate, and depositing the sifted fiber in a uniform layer n oneyor mea 3. Felting apparatus comprising conveyor means, a foraminousdrum rotatably mounted above the conveyor means, a brushing rollrotatably mounted above the drum parallel thereto and in peripheralcontact therewith; a baffle plate mounted a spaced distance ahead ofthe'brushing roll, the baffle plate being parallel to the drum and inperipheral contact therewith to form a chamber defined on three sides bythe brushing roll, baflie plate and upper surface of the drum; means forvarying the spacing between the brushing roll and the bathe plate;feeding means for feeding fiber into the chamber; and motor means forrotating the drum and the brushing roll, thereby sifting fiber throughthe drum at a rate determined by the spac ing between the brushing rolland the baffle plate, and depositing the sifted fiber in a uniform layeron the conveyor means.

4. Felting apparatus comprising conveyor means; a foraminous cylinderrotatably mounted above the conveyor means; a brushing roll rotatablymounted above the cylinder parallel thereto and in peripheral contacttherewith; a bafiie plate stationed in front of the brushing roll, thebafile plate being parallel to the cylinder and in peripheral engagementtherewith and the brushing roll, baffle plate and upper surface of thecylinder forming a chamber for the reception of the fibers; a pluralityof tumbling blocks within the cylinder; fiber feeding means for feed ingfiber into the chamber; and motor means for rotating the drum and thebrushing roll, thereby sifting the fiber through the drum and tumblingblocks, randomizing the fibers and depositing them in a uniform layer onthe conveyor means. 7

5. Felting apparatus comprising felt support means, a foraminous drumrotatably mounted across the felt support means and transverselythereof; reciprocable feeding means mounted above the drum andreciprocable in a plane parallel to the longitudinal axis of the drum;driving means for reciprocating the feeding means at a variable rate,the rate being greater at the central portion of each traverse than atthe terminal portions thereof, thereby securing uniform delivery offiber from the feeding means; and motor means for rotating the drumthereby sifting fiber deposited thereon through the same and forming itin a uniform layer on the felt support means.

6. Felting apparatus comprising conveyor means, a foraminous drumrotatably mounted above the conveyor means and transversely thereof, areciprocable fiber-feeding conduit for feeding fiber to the uppersurface of the drum in a plane parallel to the longitudinal axisthereof,

vertically arcuate flexible driving means for reciprocating the conduit,means for attaching the conduit to the driving means, and motor meansfor rotating the drum, thereby sifting the fibers therethrough anddepositing them in a uniform felt on the conveyor means.

7. The felting apparatus of claim 6 wherein the flexible driving meansfor the conduit feeding means comprises a vertically arcuate continuouschain attached to the conduit means.

8. Felting apparatus comprising felt support means, a foraminouscylinder rotatably mounted above the felt support means and extendingtransversely thereof, brushing means rotatably mounted above thecylinder parallel thereto and in peripheral contact therewith; a batheplate mounted parallel to the longitudinal axis of the cylinder andcontacting the periphery thereof, the cylinder, the baffle plate, andthe upper surface of the cylinder forming a fiber-receiving chamber;reciprocable feeding means for feeding fiber into the chamber along thelength thereof,

and motor means for rotating the cylinder, thereby sifting therethroughfiber fed into the chamber and depositing it in a uniform layer on thefelt support means.

9. Felting apparatus comprising conveyor means, a foraminous drumrotatably mounted above the conveyor. means and transversely thereof, abrushing roll rotatably mounted above the drum parallel thereto and inperipheral contact therewith, a baffle plate mounted a spaced distanceahead of the brushing roll, the baffle plate extending longitudinally ofthe drum and being in peripheral contact therewith to form with thebrushing roll a fiberreceiving chamber, reciprocable conduit means fordistributing fiber lengthwise of the fiber-receiving chamber, aplurality of tumbling blocks within the cylinder, and motor means fordriving the brushing roll and the cylinder, thereby sifting the fibersthrough the foraminous drum and tumbling blocks, and depositing thefibers a uniform layer on the conveyor means.

10. Felting apparatus comprising felting means for forming a felt ofmaterial in particle form, a conveyor positioned below the felting meansfor receiving and supporting the felted material, the conveyor having onthe upper surface thereof a plurality of rods extending transversely ofthe conveyor and spaced apart therefrom but attached thereto byconnecting members at predetermined intervals, the rods being adapted todivide the felt into blanks of predetermined size suitable forintroduction between the platens of a press.

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